1. Field of the Invention
The present invention relates to electro-mechanical door locks, and more particularly to automatic security systems for large bi-swing warehouse doors that will allow employees wearing company badges quick, hands-free access.
2. Description of Related Art
Train, airline, bus, and other transportation stations all employ gates and turnstiles to control and secure various areas. These gates very often have to be able to swing both ways and yet be able to latch securely. Station agents in secure booths need to be able to unlock the gates briefly to let authorized riders and ticketholders through. Very often the way this is done in conventional systems is to use an electro-mechanical lock mechanism at the gate with wires buried in the ground or installed in the floors and walls connected to a control switch in the secure booth.
Such lock systems must survive energetic efforts by criminals to kick the gates down, and still be failsafe in the event of a power failure. The gates must unlatch when power is lost so as to not trap people from escape.
David Dudley describes such a locking mechanism for a bi-swing train station gate in U.S. Pat. No. 8,186,729, issued May 29, 2012, titled TRAPLOCK FOR BI-SWING GATE (Dudley '729).
When two large bi-swing doors are used together, such as in large liquor distribution warehouses, there is no vertical post in which a Traplock like that described by Dudley '729 can be installed. Such Traplock will not work if it is installed horizontally in the overhead door casings because the solenoids and latches will be pulled into a lockup situation by the new ways gravity is acting on them.
As an example of an installation, the FRANK ColdSwing Double Acting Cold Storage Door is used for personnel, hand truck and pallet jack traffic. The design provides quick and easy, hands-free access between separated environmentally controlled spaces. It facilitates continuous movements of people, hand trucks, and pallet jack traffic in cooler applications. These doors have windows in them, and match the performance of more traditional cold storage doors. See, frankdoor.com/product_line_double_acting_doors.php
There is also a need to minimize the construction expense of having to retrofit new locking systems into existing warehouse buildings and security doors. Not having to replace or modify the existing doors is a primary consideration. Tearing up concrete or tiled floors to lay wires is also just out of the question.